Tokamak control and plasma safety
Holding a burning plasma inside its magnetic cage — and staying inside the safety envelope.
A tokamak confines a hot plasma with magnetic fields whose shape and position must be actively maintained on a millisecond timescale. Control means driving the coil currents so that the plasma keeps its intended shape, current, and position, while never leaving the operating window in which the device is safe. It is a real-time control problem coupled to a high-dimensional physical system.
Two threats define the safety boundary. The plasma can drift out of its intended configuration, and it can disrupt — a sudden, damaging loss of confinement. Modern approaches combine learned controllers with predictors that estimate how close the plasma is to a disruption, so the controller can act before the boundary is crossed rather than after.
The control studio models this as an evidence problem: a control decision is only as trustworthy as the boundary it was verified within. Every result carries its claim boundary verbatim — a bounded-model result is never presented as a validated one — so a safety-envelope score is read together with the conditions under which it holds.
The vocabulary of the topic.
- Magnetic equilibrium
- The balance of magnetic and plasma pressure that holds the plasma in shape; the thing control maintains.
- Disruption
- A rapid, damaging loss of plasma confinement; the event predictors are built to anticipate.
- Safety envelope
- The operating window within which the device is safe; a control claim is only valid inside it.
- Real-time control
- Actuation on the plasma's own millisecond timescale, from measurements to coil currents.
Studios working on this.
Each runs standalone in its own repository and federates its evidence through the platform.
Run it, don't take it on faith.
The runnable lessons and sealed measurements this site ships for the topic.
Read it at source, in order.
Canonical references for the topic, ordered from the foundations to current work. Every one was verified at source — a DOI resolves through doi.org, a standard through its issuer — so each link goes to the real record.
Current work
- 1
Learned magnetic control demonstrated on the TCV tokamak.
- 2
Disruption prediction — the safety problem a control studio must respect.
Related topics.
Where this topic connects to the rest of the federation's work.